Auditory neuropathy/auditory dys-synchrony (AN/AD) is a category of hearing loss characterized by present outer hair cell function, asynchronous neural activity, and unusually poor speech perception ability. Beyond these distinguishing features, the hearing-loss characteristics of the AN/AD population are highly heterogeneous, including the responses to different intervention approaches such as hearing aids and cochlear implants. There are several possible causes for AN/AD, which if known may lead to early and appropriate intervention strategies. However, pinpointing the underlying cause for a given case of AN/AD is currently beyond our clinical abilities. It is possible that genetic anomalies may be related to specific audiologic features of AN/AD, and that these relationships may be used for early identification and subsequent intervention of specific subgroups of AN/AD. For this study it is hypothesized that canaidate mutations will be identified in the general clinical population with AN/AD, and that these mutations significantly increase the risk of having AN/AD. There are two Specific Aims: 1) To retrospectively and prospectively define phenotipic characteristics of AN/AD, and 2) To test for genetic mutations that are associated with AN/AD and other neuropathies. For Aim 1, comprehensive testing of AN/AD will include obtaining health information;audiometric testing;objective measures;and speech perception testing in quiet and in noise, including hearing aid and cochlear implant users. These measures will be repeated throughout the duration of the study. For Aim 2, DMA from buccal swabs will be obtained from AN/AD subjects and a control group of normal-hearing children. The DMA will undergo single nucleotide polmorphism (SNP) analyses for candidate mutations known to be associated with AN/AD, SNHL, and peripheral neuropathy in general. The Candidate has experience in auditory neurophysiology and clinical audiology, therefore the training aspect for the Candidate will be in developing skills in genetic research. By aiming to identify genetic mutations associated with the variety of causes and characteristics of AN/AD, this study has the potential to significantly impact the identification of AN/AD subtypes, which may lead to earlier intervention and treatment plans for these individuals.